Motor vehicle door locks of the above design, as commonly used in industry and which are, for instance, described in the generic DE 35 26 501 A1, typically contain an arrangement in which an external actuation lever, an external locking lever or also other levers such as internal actuation levers, internal locking levers, etc. extend to the outside through associated openings in the lock housing. This is necessary as said levers are generally mechanically coupled to manipulation elements arranged remotely from the motor vehicle door lock in a motor vehicle door via interposed connecting elements such as Bowden cables, rods or similar.
The external actuation lever is, for instance, mechanically coupled to an external door handle, arranged remotely from the lock housing on the outside of a motor vehicle door. The external locking lever may be mechanically coupled to a locking cylinder provided in an area of the external door handle.
An additionally provided internal door handle acts on the internal actuation lever and an internal locking head is mechanically connected to the internal locking lever in the shown example. Although some of these individual functions have nowadays at least partially been automated by a motor provided inside the lock housing being respectively electrically controlled from the outside, one or more levers still extend through associated openings out of the lock housing. This is due to safety reasons and in order to provide a required back-up ensuring the main functions of the motor vehicle door lock also in case of an electrical fault.
Such openings in the lock housing are problematic, as regards the service life of the motor vehicle door lock and its unchanged functionality. The opening allows dust, dirt and humidity to enter the inside of the motor vehicle door lock. In extreme cases this can cause corrosion which cannot only impair functionality but stop its functioning altogether.
Further prior art as disclosed in DE 199 20 278 A1 shows approaches to tightly seal the lock housing. For this purpose, the lock housing of this prior art embodiment is fully enclosed. In addition, associated operating elements are all located outside of the lock housing and interact with closing elements and/or locking/actuating elements via connecting elements mounted in the lock housing. This means that by relying on obligatory connecting elements between the actuating elements and the closing elements or locking/actuating elements, a relative complex and expensive design is required. This arrangement also lacks flexibility at this point as a separate design must be developed and implemented for each motor vehicle door lock or associated lock housing.
In further prior art the lock housing already contains an integral seal. In this context, EP 0 940 241 A2 discloses a method for producing a lock housings with an integral seal, produced from a plastic material by injection moulding. The problem of the required openings for levers projecting out of the lock housing is, however, not mentioned at this point.
The same applies for the composite element made from thermoplastic and polyurethane elastomer with the addition of a bonding agent, disclosed in DE 198 58 270 A1. This composite element can also be a door lock housing with sealing lips, without the position and arrangement of the sealing lips being disclosed in detail.